With the advances in technology and medicine, implants, such as bone screws, are used to fix the biological tissue in the human body for medical purpose, for example, for repairing accidental injury or nature aging. However, modulus of elasticity of the conventional implants is much higher than that of the biological tissue in the human body. When the force applied to the human body is too high, the biological tissue tends to necrosis or wear, and the implants may also be loosened.
In general, pores are disposed on the implants, such as bone screws to lower the modulus of elasticity. However, the conventional process of manufacturing implants includes a special sintering process or a surface coating process, and then executing a pore-opening by laser. Positions of the pores generated by such method may not be fixed, the pores are not connected to each other, and formed only on the surface of the implants, such that the porosity of the pores may be uncertain. Besides, it may be hard to form pores with regular shape by the conventional process. If the pores are too large, then lack of rigidity may generate problems such as implants loosening or breaking after implantation of bone healing or long-term use. On the contrary, if the pores are too small, then problems that the biological tissue tends to necrosis and wear mentioned above may not be solved.